Claw rotor for axial flux rotating electric machine and associated rotating electric machine

Abstract

The present invention relates to a claw rotor (1, 1') for a rotating electrical machine with axial flux (10), said rotor (1, 1') comprising: - a first (3a) and a second (3b) pole wheels configured to be assembled together to form a core (11), said core (11) being configured to extend around a central shaft of the rotating electrical machine (10), said first (3a) and second (3b) pole wheels comprising a plurality of claws (5) extending radially around the core (11), - at least one coil (13) configured to be arranged around the core (11) and to be energized to form an excitation source for the rotating electrical machine (10). Figure for the abstract: Fig. 1

Description

Title of the invention: Claw rotor for axial flux rotating electric machine and associated rotating electric machine

[0001] The present invention is part of the field of axial flux rotating electric machines or motors, that is to say in which the magnetic flux circulates axially between the stator(s) and the rotor(s).

[0002] Axial flux machines are of interest, particularly in electric or hybrid vehicles, because of their energy density which makes it possible to obtain a motor with a reduced size and a high torque.

[0003] However, in order to obtain significant power with such machines, it is necessary to use one or more rotors having a significant amount of permanent magnets, which makes their manufacture expensive.

[0004] It is therefore necessary to find a solution enabling the production of a rotor for a rotating electrical machine with axial flux at a reduced cost.

[0005] To this end, the present invention relates to a claw rotor for a rotating electrical machine with axial flux, said rotor comprising: - a first and a second pole wheel configured to be assembled together to form a core, said core being configured to extend around a central shaft of the rotating electrical machine, said first and second pole wheels comprising a plurality of claws extending radially around the core, - at least one coil configured to be arranged around the core and to be energized to form an excitation source for the rotating electrical machine.

[0006] Such a rotor makes it possible to obtain an excitation source made by a coil which makes it possible to reduce the cost of the rotor due to the absence or the smaller quantity of permanent magnets required.

[0007] According to another aspect of the present invention, the rotor also comprises a plurality of permanent magnets arranged between the claws of the first and second pole wheels, the permanent magnets extending radially around the, at least one, coil to form an additional excitation source for the rotating electrical machine.

[0008] According to another aspect of the present invention, the core is formed by the first or second pole wheels.

[0009] According to another aspect of the present invention, the core is formed by a first half-core associated with the first pole wheel and a second half-core associated with the second pole wheel.

[0010] According to another aspect of the present invention, the claws of the first or second pole wheel have at least one magnetic chamfer which makes it possible to improve the acoustics of the rotor.

[0011] According to another aspect of the present invention, the first and second pole wheels are made of ferromagnetic material.

[0012] According to another aspect of the present invention, the first and / or second pole wheel is a single piece element and not a sheet of metal, which simplifies manufacturing and therefore reduces the cost of the rotor.

[0013] The present invention also relates to a rotating axial flux electrical machine comprising at least one rotor as described above.

[0014] According to another aspect of the present invention, the rotating electrical machine comprises a central rotor and two stators arranged axially on either side of the central rotor.

[0015] According to another aspect of the present invention, the rotor includes one or more additional pole wheels, such as for example an assembly comprising two first pole wheels joined together and two second pole wheels, to allow interaction with the two stators.

[0016] According to another aspect of the present invention, the rotating electrical machine comprises two rotors arranged axially on either side of a central stator.

[0017] Other features and advantages of the invention will become more apparent upon reading the following description, given by way of illustrative and non-limiting example, and the accompanying drawings, among which:

[0018] [Fig-1] represents a schematic perspective view of a claw rotor according to an embodiment of the present invention;

[0019] [Fig.2] represents an exploded schematic view of the rotor of the [Fig.1];

[0020] [Fig.3] represents a schematic perspective view of a first polar wheel of the rotor of the [Fig.1];

[0021] [Fig.4] represents a schematic perspective view of a second pole wheel of the rotor of the [Fig.1];

[0022] [Fig.5] represents a schematic perspective view of a rotating axial flux electrical machine according to an embodiment of the present invention;

[0023] [Fig.6] represents a schematic perspective view of a stator of the rotating electrical machine of [Fig.5];

[0024] [Fig.7] represents a schematic perspective view of a stator armature of [Fig.6];

[0025] [Fig.8] represents a schematic perspective view of a stator coil of [Fig.6];

[0026] [Fig.9] represents a schematic perspective view of a rotor according to another embodiment of the present invention;

[0027] [Fig. 10] represents a schematic perspective view of the rotor of the [Fig.9] in which a second pole wheel has been removed;

[0028] [Fig. 11] represents a schematic perspective view of a retaining strip for permanent magnets;

[0029] In these figures, identical elements bear the same references.

[0030] The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features from different embodiments can also be combined or interchanged to provide other embodiments.

[0031] The present invention relates to a rotating electrical machine (or electric motor) with axial flux 10, that is to say a machine in which the stator and the rotor are arranged so as to create a magnetic field extending in a direction parallel to the axial direction (relative to the axis of rotation of the rotor) and in particular a rotor of such a rotating electrical machine 10.

[0032] The present invention relates in particular to a claw rotor as shown in [Fig. 1] of such a rotating electrical machine 10. The rotor 1 is formed by a first pole wheel 3a (best shown in [Fig. 3]) and a second pole wheel 3b (best shown in [Fig. 4]), each comprising a plurality of claws 5, eight claws each in the example shown. The claws 5 of the first pole wheel 3a are configured to interlock with the claws 5 of the second pole wheel 3b in the assembled state of the rotor 1. For this purpose, the claws 5 of at least one of the pole wheels 3a, 3b extend axially (in the present case, the claws 5 of the first pole wheel 3a extend axially). The first 3a and second 3b pole wheels include a central through-hole configured to receive a central shaft of the rotating electrical machine.The first 3a and second 3b pole wheels can be made in a single piece by machining a block of ferromagnetic material, for example steel, and not from rolling different layers.

[0033] The rotor 1 may also include a set of permanent magnets 7 arranged between the claws 5 of the first 3a and second 3b pole wheels. The permanent magnets 7 are, for example, attached to the claws 5 of the first 3a or second 3b pole wheels by laminations 15 (visible in [Fig. 11]), i.e., material recesses forming a groove or pocket whose shape is complementary to the shape of the permanent magnet 7 coupled to a ratcheting device for holding the permanent magnet 7 in position during the assembly of the rotor 1 and during the life of the rotating electrical machine. The claws 5 of the first 3a and / or second 3b pole wheels may also include magnetic chamfers 9 in order to improve the acoustics of the rotor 1.

[0034] As can be seen more clearly in the exploded view of [Fig.2], the first 3a and second 3b pole wheels also form a core 11 configured to extend around the central shaft of the rotating electrical machine.

[0035] According to a first embodiment shown in [Fig.2], the core 11 can be formed in the second polar wheel 3b.

[0036] According to a second embodiment (not shown), the core 11 can be formed in the first polar wheel 3a.

[0037] According to a third embodiment (not shown), the core 11 can be formed by two half-cores formed respectively in the first 3a and the second 3b pole wheels.

[0038] The rotor 1 also includes one or more coils 13 (a single coil 13 in the example of [Fig.2]) configured to be arranged around the core 11.

[0039] The coil 13 is for example made by winding a coil around the core 11.

[0040] The coil 13 is configured to be powered to form an excitation source for the axial flux rotating electric machine 10. The power supply is for example provided by a brush-collector assembly which allows the coil 13 to be powered despite the rotation of the rotor 1.

[0041] Thus, in the example of [Fig.2], the rotor 1 has a double excitation, on the one hand via the coil 13 and on the other hand via the permanent magnets 7.

[0042] The use of double excitation makes it possible to obtain a rotating electrical machine with significant power and torque while limiting the quantity of permanent magnets 7. If the power required for the rotating electrical machine is low, for example less than 80 kW, it is also possible to do without the permanent magnets 7 completely and to have a single excitation via the coil(s) 13.

[0043] Different rotor 1 configurations can be used, in particular depending on the configuration of the axial flux rotating electrical machine.

[0044] According to an embodiment shown in [Fig.5], the rotating electric machine 10 comprises a central stator 2, a first rotor la and a second rotor 1b arranged on either side of the central stator 2. The first la and the second 1b rotors are for example similar to the rotor 1 shown previously in Figures 1 and 2.

[0045] As shown in [Fig. 6], the stator 2 may include an armature 21 (best seen in [Fig. 7]) on which coils 23 are arranged. [Fig. 8] shows an example of a coil 23 configured to be arranged on the armature 21 of the [Fig.7]. The stator 2 comprises a first series of coils 23 arranged opposite the first rotor 1a and configured to drive the first rotor 1a in rotation both via the coil 13 and via the permanent magnets 7 of the first rotor 1a and a second series of coils 23 arranged opposite the second rotor 1b and configured to drive the second rotor 1b in rotation both via the coil 13 and via the permanent magnets 7 of the second rotor 1b.

[0046] According to another embodiment, the rotating electrical machine 10 may comprise a central rotor 1' and two stators 2 arranged on either side of the central rotor. In this case, the central rotor 1' may correspond to two rotors 1 as described above, joined together. Figures 9 and 10 represent such a central rotor 1'. In [Fig. 10], one of the pole wheels 3b is not shown to make the other elements more visible. Thus, the central rotor 1' comprises two first pole wheels 3a joined together to form an assembly, the claws of the first pole wheels 3a extending axially on one side and then the other of the assembly. The central rotor 1' also comprises two second pole wheels 3b configured to be positioned on one and a second side of the assembly formed by the first two pole wheels 3a.The first and second pole wheels form a first and second core 11 around which are arranged a first and second coil 13. Permanent magnets 7 are also arranged between the claws of the first and second pole wheels. Thus, the central rotor 1' can interact with a first stator 2 arranged axially on a first side of the central rotor 1' and with a second stator 2 arranged axially on a second side of the central rotor 1' opposite the first side.

[0047] Thus, the use of a claw rotor 1, 1' for a rotating electrical machine with axial flux 10 comprising at least one coil 13 configured to interact with a stator 2 to drive said rotor 1, 1' in rotation makes it possible to reduce the quantity of permanent magnets 7 required for the operation of the rotating electrical machine 10 or even to eliminate the use of permanent magnets 7 which makes it possible to reduce the cost of the rotating electrical machine 10.

[0048] Of course, the preceding description has been given by way of example only and does not limit the scope of the invention, which would not be exceeded by replacing the various elements with any other equivalents.

[0049] Furthermore, the different features, variants, and / or embodiments of the present invention can be combined with each other in various ways, provided that they are not incompatible or mutually exclusive.

Claims

Demands

1. A rotating axial flux electric machine (10) comprising at least one claw rotor (1, 1'), said rotor (1, 1') comprising: • a first (3a) and a second (3b) pole wheels configured to be assembled together to form a core (11), said core (11) being configured to extend around a central shaft of the rotating electric machine (10), said first (3a) and second (3b) pole wheels comprising a plurality of claws (5) extending radially around the core (11), • at least one coil (13) configured to be arranged around the core (11) and to be energized to form an excitation source for the rotating electric machine (10), • a plurality of permanent magnets (7) arranged between the claws (5) of the first (3a) and second (3b) pole wheels, the permanent magnets (7) extending radially around 1' at least one,coil (13) to form an additional excitation source for the rotating electrical machine (10).

2. Axial flux rotating electric machine (10) according to claim 1 in which the core (11) is formed by the first (3a) or the second (3b) pole wheels.

3. Axial flux rotating electric machine (10) according to claim 1 in which the core (11) is formed by a first half-core associated with the first pole wheel (3a) and a second half-core associated with the second pole wheel (3b).

4. Axial flux rotating electric machine (10) according to any one of the preceding claims wherein the claws (5) of the first (3a) or second (3b) pole wheel have at least one magnetic chamfer (9).

5. Axial flux rotating electric machine (10) according to any one of the preceding claims wherein the first (3a) and second (3b) pole wheels are made of ferromagnetic material.

6. Axial flux rotating electric machine (10) according to any one of the preceding claims wherein the first (3a) and / or the second (3b) pole wheel is a single-piece element.

7. Rotating electric machine (10) according to any one of the preceding claims comprising a central rotor (1') and two stators (2) arranged axially on either side of the central rotor (1').

8. Rotating electric machine (10) according to any one of the preceding claims wherein the rotor (1') comprises one or more additional pole wheels to enable interaction with the two stators (2).

9. Rotating electric machine (10) according to any one of claims 1 to 6 comprising two rotors (1) arranged axially on either side of a central stator (2).

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